why all Azure pipelines are triggered by merging a pull request to Main branch?

I have two pipelines setup on a GitHub repo ProjectA, one for building ProjectA (DEMO-ProjectA) and another for the Veracode scan of the binaries(DEMO-ProjectA-Veracode).

And there are three branches in repo ProjectA: Main, Dev, Veracode.

I committed some code change to branch Dev and the pipeline DEMO-ProjectA was triggered,then I created a pull request on Dev and try to merge the code change to Main, Both DEMO-ProjectA and DEMO-ProjectA-Veracode are triggered, I was expecting only the DEMO-ProjectA is triggered? Why? Does this works as designed or there is something wrong with my trigger setup?

Below are triggers for two pipeline

DEMO-ProjectA:

trigger:
  branches:
    include:
    - Main
    - Dev
    exclude:
    - Veracode
  paths:
    include:
    -
    exclude:
    - azure-pipelines.yml
    - veracode-scan.yml

DEMO-ProjectA-Veracode:

trigger:
  branches:
    include:
    - Veracode
    exclude:
    - Main
    - Dev
  paths:
    include:
    -
    exclude:
    - azure-pipelines.yml
    - veracode-scan.yml